Electronic Materials Letters

, Volume 15, Issue 2, pp 253–265 | Cite as

Geometrical Effects of Cu@Ag Core–Shell Nanoparticles Treated Flux on the Growth Behaviour of Intermetallics in Sn/Cu Solder Joints

  • Shengyan Shang
  • Anil Kunwar
  • Yanfeng Wang
  • Jinye Yao
  • Yingchao Wu
  • Haitao MaEmail author
  • Yunpeng WangEmail author
Original Article - Theory, Characterization and Modeling


Solder ball of initial diameter 1.4 mm, was reflow soldered with Cu substrate at 523.15 K using flux doped with Cu@Ag core–shell nanoparticles (NPs) in the proportion 0–2 wt%. The solders were then air cooled to room temperature. The use of NPs, by reducing the base height (H) of the solder and enhanced the diameter (W) of the solder, caused an overall increase in the spread ratio of the solder. The altered magnitudes of heat and mass transfer in these geometrically different but constant volume specimens were analyzed using finite element method. The occurrence of differential concentration gradient, radial thermal gradient and velocity magnitudes, in solders with differing geometry were numerically elaborated. The \(\hbox {Cu}_{6}\hbox {Sn}_{5}\)intermetallic compound (IMC) formed at the Cu/Sn interface, was obtained to be the thickest for the specimen using undoped flux, whereas it was found to be smallest for the sample processed with flux containing 0.5% NPs. From the growth kinetics study, it has been inferred that IMC thickness is linearly proportional to the geometrical parameter H and \(\hbox {W}^b\), with b < 1.

Graphical Abstract


Electronic materials Intermetallic compounds Crystal growth Thermogravimetric analysis Diffusion Finite element method 



This work was supported by the National Natural Science Foundation of China (Grant Nos: 51871040 and 51571049), “Research Fund for International Young Scientists” of National Natural Science Foundation of China (Grant Number: 51750110504) and China Postdoctoral Science Foundation (Grant Number: 2017M611215).


  1. 1.
    Annuar, S., Mahmoodian, R., Hamdi, M., Tu, K.-N.: Intermetallic compounds in 3D integrated circuits technology: a brief review. Sci. Technol. Adv. Mater. 18(1), 1–11 (2017)CrossRefGoogle Scholar
  2. 2.
    Tu, K.N., Liu, Y., Li, M.: Effect of Joule heating and current crowding on electromigration in mobile technology. Appl. Phys. Rev. 4(1), 011101 (2017)CrossRefGoogle Scholar
  3. 3.
    Chang, C.C., Lin, Y.W., Wang, Y.W., Kao, C.R.: The effects of solder volume and cu concentration on the consumption rate of Cu pad during reflow soldering. J. Alloys Compd. 492(1), 99–104 (2010)CrossRefGoogle Scholar
  4. 4.
    Islam, M.N., Sharif, A., Chan, Y.C.: Effect of volume in interfacial reaction between eutectic Sn–3.5Ag–0.5Cu solder and Cu metallization in microelectronic packaging. J. Electron. Mater. 34(2), 143–149 (2005)CrossRefGoogle Scholar
  5. 5.
    Liu, L., Huang, M.: Effect of solder volume on interfacial reactions between Sn3.5Ag0.75Cu solder balls and Cu pad. In: International Conference on Electronic Packaging Technology and High Density Packaging, pp. 299–304 (2010)Google Scholar
  6. 6.
    Shen, J., Chan, Y.C.: Effect of metal/ceramic nanoparticle-doped fluxes on the wettability between Sn–Ag–Cu solder and a Cu layer. J. Alloys Compd. 477(1–2), 909–914 (2009)CrossRefGoogle Scholar
  7. 7.
    Shang, S., Kunwar, A., Wang, Y., Yao, J., Ma, H., Wang, Y.: Synthesis of Cu@Ag core–shell nanoparticles for characterization of thermal stability and electric resistivity. Appl. Phys. A Mater. Sci. Process. Submitted (2018)Google Scholar
  8. 8.
    Shang, S., Kunwar, A., Wu, Y., Ma, H.: Effects of Cu nanoparticles doped flux on the microstructure of IMCs between Sn solder and Cu substrate. In: International Conference on Electronic Packaging Technology, pp. 1577–1581. IEEE (2017)Google Scholar
  9. 9.
    Ribes, A., Caremoli, C.: Salome platform component model for numerical simulation. In: 31st Annual International Computer Software and Applications Conference, (COMPSAC 2007), (Compsac), vol. 2, pp. 553–564 (2007)Google Scholar
  10. 10.
    Rizvi, M.J., Lu, H., Bailey, C.: Modeling the diffusion of solid copper into liquid solder alloys. Thin Solid Films 517(5), 1686–1689 (2009)CrossRefGoogle Scholar
  11. 11.
    Kunwar, A., Ma, H., Ma, H., Sun, J., Zhao, N., Huang, M.: On the increase of intermetallic compound’s thickness at the cold side in liquid Sn and SnAg solders under thermal gradient. Mater. Lett. 172, 211–215 (2016)CrossRefGoogle Scholar
  12. 12.
    Kunwar, A., Guo, B., Shang, S., Raback, P., Wang, Y., Chen, J., Ma, H., Song, X., Zhao, N.: Roles of interfacial heat transfer and relative solder height on segregated growth behavior of intermetallic compounds in Sn/Cu joints during furnace cooling. Intermetallics 93, 186–196 (2018)CrossRefGoogle Scholar
  13. 13.
    Malinen, M., Raback, P.: Elmer finite element solver for multiphysics and multiscale problems. Multiscale Model. Methods Appl. Mater. Sci. 19, 101–113 (2013)Google Scholar
  14. 14.
    Ayachit, U., Bauer, A., Chaudhary, A., DeMarle, D., Geveci, B., Jourdain, S., Lutz, K., Marion, P., Maynard, R., Shetty, N., Yuan, Y.: The ParaView Guide. Kitware Inc., ParaView, New York (2008)Google Scholar
  15. 15.
    Cheung, N., Santos, N.S., Quaresma, J.M.V., Dulikravich, G.S., Garcia, A.: Interfacial heat transfer coefficients and solidification of an aluminum alloy in a rotary continuous caster. Int. J. Heat Mass Transf. 52(1–2), 451–459 (2009)CrossRefGoogle Scholar
  16. 16.
    Gancarz, T., Moser, Z., Gasior, W., Pstrus, J., Henein, H.: A comparison of surface tension, viscosity, and density of sn and snag alloys using different measurement techniques. Int. J. Thermophys. 32(6), 1210–1233 (2011)CrossRefGoogle Scholar
  17. 17.
    Meydaneri, F., Gunduz, M., Ozdemir, M., Saatci, B.: Determination of thermal conductivities of solid and liquid phases for rich-Sn compositions of Sn–Mg alloy. Met. Mater. Int. 18(1), 77–85 (2012)CrossRefGoogle Scholar
  18. 18.
    Gancarz, T., Gasior, W., Henein, H.: Physicochemical properties of Sb, Sn, Zn, and Sb–Sn system. Int. J. Thermophys. 34(2), 250–266 (2013)CrossRefGoogle Scholar
  19. 19.
    Ma, H., Kunwar, A., Guo, B., Sun, J., Jiang, C., Wang, Y., Song, X., Zhao, N., Ma, H.: Effect of cooling condition and Ag on the growth of intermetallic compounds in Sn-based solder joints. Appl. Phys. A Mater. Sci. Process. 122(12), 1–10 (2016)CrossRefGoogle Scholar
  20. 20.
    Kunwar, A., Givernaud, J., Ma, H., Meng, Z., Shang, S., Wang, Y., Ma, H.: Modelling the melting of Sn0.7Cu solder using the enthalpy method. In: International Conference on Electronic Packaging Technology, Wuhan, China, pp. 166–169 (2016)Google Scholar
  21. 21.
    Bo, S., Lu, X.G., Ohtani, H.: The implementation of an algorithm to calculate thermodynamic equilibria for multi-component systems with non-ideal phases in a free software. Comput. Mater. Sci. 101, 127–137 (2015)CrossRefGoogle Scholar
  22. 22.
    Bo, S., Kattner, U.R., Palumbo, M., Fries, S.G.: Opencalphad—a free thermodynamic software. Integr. Mater. Manuf. Innov. 4(1), 1 (2015)CrossRefGoogle Scholar
  23. 23.
    Tay, S.L., Haseeb, A.S.M.A., Johan, M.R., Munroe, P.R., Quadir, M.Z.: Influence of Ni nanoparticle on the morphology and growth of interfacial intermetallic compounds between Sn–3.8Ag–0.7Cu lead-free solder and copper substrate. Intermetallics 33, 8–15 (2013)CrossRefGoogle Scholar
  24. 24.
    Chan, Y.H., Arafat, M.M., Haseeb, A.S.M.A.: Effects of reflow on the interfacial characteristics between Zn nanoparticles containing Sn–3.8Ag–0.7Cu solder and copper substrate. Solder. Surf. Mt. Technol. 25(2), 91–98 (2013)CrossRefGoogle Scholar
  25. 25.
    Li, Y., Chan, Y.C.: Effect of silver (Ag) nanoparticle size on the microstructure and mechanical properties of Sn58BiAg composite solders. J. Alloys Compd. 645, 566–576 (2015)CrossRefGoogle Scholar
  26. 26.
    Arenas, M.F., Acoff, V.L.: Contact angle measurements of Sn–Ag and Sn–Cu lead-free solders on copper substrates. J. Electron. Mater. 33(12), 1452–1458 (2004)CrossRefGoogle Scholar
  27. 27.
    Bhanushali, S., Ghosh, P., Ganesh, A., Cheng, W.: 1D copper nanostructures: progress, challenges and opportunities. Small 11(11), 1232–1252 (2015)CrossRefGoogle Scholar
  28. 28.
    Saiz, E., Tomsia, A.P., Rauch, N., Scheu, C., Ruehle, M., Benhassine, M., Seveno, D., De Coninck, J., Lopez-Esteban, S.: Nonreactive spreading at high temperature: molten metals and oxides on molybdenum. Phys. Rev. E Stat. Nonlinear Soft Matter Phys. 76(4), 1–15 (2007)CrossRefGoogle Scholar
  29. 29.
    Aarts, D.G.A.L., Lekkerkerker, H.N.W., Guo, H., Wegdam, G.H., Bonn, D.: Hydrodynamics of droplet coalescence. Phys. Rev. Lett. 95(16), 1–4 (2005)Google Scholar
  30. 30.
    Bhardwaj, R., Longtin, J.P., Attinger, D.: A numerical investigation on the influence of liquid properties and interfacial heat transfer during microdroplet deposition onto a glass substrate. Int. J. Heat Mass Transf. 50(15–16), 2912–2923 (2007)CrossRefGoogle Scholar
  31. 31.
    Tran, A.T.T., Hyland, M.M., Shinoda, K., Sampath, S.: Influence of substrate surface conditions on the deposition and spreading of molten droplets. Thin Solid Films 519(8), 2445–2456 (2011)CrossRefGoogle Scholar
  32. 32.
    Tran, A.T.T., Hyland, M.M., Shinoda, K., Sampath, S.: Inhibition of molten droplet deposition by substrate surface hydroxides. Surf. Coat. Technol. 206(6), 1283–1292 (2011)CrossRefGoogle Scholar
  33. 33.
    Silva, B.L., Cheung, N., Garcia, A., Spinelli, J.E.: Evaluation of solder/substrate thermal conductance and wetting angle of Sn–0.7 wt%Cu-(0–0.1 wt%Ni) solder alloys. Mater. Lett. 142, 163–167 (2015)CrossRefGoogle Scholar
  34. 34.
    Zhang, Z.H., Cao, H.J., Yang, H.F., Li, M.Y., Yu, Y.X.: Hexagonal-rod growth mechanism and kinetics of the primary Cu6Sn5 phase in liquid Sn-based solder. J. Electron. Mater. 45(11), 5985–5995 (2016)CrossRefGoogle Scholar
  35. 35.
    Haseeb, A.S.M.A., Leong, Y.M., Arafat, M.M.: In-situ alloying of Sn–3.5Ag solder during reflow through Zn nanoparticle addition and its effects on interfacial intermetallic layers. Intermetallics 54, 86–94 (2014)CrossRefGoogle Scholar
  36. 36.
    Meng, F., Morin, S.A., Forticaux, A., Jin, S.: Screw dislocation driven growth of nanomaterials. Acc. Chem. Res. 46(7), 1616–1626 (2013)CrossRefGoogle Scholar
  37. 37.
    Gusak, A.M., Tu, K.N.: Kinetic theory of flux-driven ripening. Phys. Rev. B Condens. Matter Mater. Phys. 66(11), 1–14 (2002)CrossRefGoogle Scholar
  38. 38.
    Li, J.F., Mannan, S.H., Clode, M.P., Whalley, D.C., Hutt, D.A.: Interfacial reactions between molten Sn–Bi–X solders and Cu substrates for liquid solder interconnects. Acta Mater. 54(11), 2907–2922 (2006)CrossRefGoogle Scholar
  39. 39.
    Dybkov, V.I.: Growth Kinetics of Chemical Compound Layers. Cambridge International Science Publishing, Cambridge (1998)Google Scholar

Copyright information

© The Korean Institute of Metals and Materials 2019

Authors and Affiliations

  1. 1.School of Materials Science and EngineeringDalian University of TechnologyDalianChina
  2. 2.School of Mechanical EngineeringDalian University of TechnologyDalianChina
  3. 3.Department of Materials EngineeringKU LeuvenLeuvenBelgium

Personalised recommendations